Android: When you place or receive a call, Noteify pops up in a floating window with all the information you would need about that contact, almost like an assistant with a cheat sheet for the things you need to know or remember.

Most such apps only have the option to add a note about the contact, which pops up on call—and Noteify has that, complete with rich text editing. But in addition to that, Noteify also has the contact's details from your phone book, so you can edit or access that information if need be. The nice part about this is that you can also edit contact details while on the call in case there has been a change.

Noteify is completely free and works just as advertised. It's highly customizable in layout and appearance, so tinker around and set it how you like it.